Electromagnetic Radiation

Transcription

1 Teacher Edition EMR: Investigation 3 Integrative Science, Technology, Engineering, and Mathematics Electromagnetic Radiation Investigation 2 Electromagnetic Spectrum Instructional Objectives Students will: explain the electromagnetic spectrum and calculate wavelength based on the electromagnetic spectrum.; calculate wavelength using C = wavelength x frequency. Background This investigation is part of the EMR Unit of the Robotics and Engineering Design Curriculum. How can EMR be collected and measured? Do you listen to the radio, watch TV, or use a microwave oven? All these devices make use of electromagnetic waves. Radio waves, microwaves, visible light, and x rays are all examples of electromagnetic waves that differ from each other in wavelength. The motion of electrically charged particles produces electromagnetic waves. These waves are also called "electromagnetic radiation" because they radiate from the electrically charged particles. They travel through empty space as well as through air and other substances. This investigation will explore the range on the electromagnetic spectrum and investigate how the waves can be collected and measured. Funding by the Georgia Department of Education through the U.S. Department of Education Race to the Top. Center for Education Integrating Science Mathematics and Computing- CEISMC 149

2 Teacher Edition EMR: Investigation 3 Materials Spectrum slide Vocab PPT EMR Graphic Slide Radio waves and the electromagnetic spectrum Lesson Plan I- Pads with Oscilloscope Overview Investigations 2 through 7 will follow the phases of the 7- E Instructional Model in which students can construct new learning based on prior knowledge and experiences. The time allotted for each activity is approximate and can be adjusted per the discretion of the teacher FUNDING BY THE GEORGIA DEPARTMENT OF EDUCATION THROUGH THE U.S. DEPARTMENT OF EDUCATION RACE TO THE TOP CENTER FOR EDUCATION INTEGRATING SCIENCE MATHEMATICS AND COMPUTING- CEISMC

3 Teacher Edition EMR: Investigation Investigation 3.1 Explain (40 minutes) Preparation: Load the following link (video) on the teacher s computer for display Group Work Overview: Explain Students understand characteristics of waves. Students calculate wavelength and frequency. Materials: Student Sheets Radio Waves and Computers. Opening (3-5 min): In the engineering notebook, have students describe what a wave is to them. Student Actions Teacher Actions Level and Indicator of Understanding Part 1: 10 Min Introduction to the EMR Spectrum Students view the introduction video of the EMR Spectrum. Introduce EMR video and guide student discussions. Students support their statements with the observations and conclusions made from watching the video. Part 2 25 min Radio Waves/Calculating Wavelength and Frequency. Student will calculate wavelength using student sheet from EM handout. Student practice with the equation Explain and discuss the concepts of waves and wavelengths. Explain how to calculate frequency and wavelength using the appropriate formula. Students complete Radio Waves Student Sheet.

4 Teacher Edition EMR: Investigation Daily Plan Investigation 3.1 Explain (~40 minutes) Essential Questions: How can EMR be collected and measured? Suggested Activities Opening: 3-5 Min 1. In the engineering notebook, have students describe what a wave is to them. Part 1: 10 Min - Introduction to the EMR Spectrum 1. Show the video the Introduction to the Electromagnetic Spectrum Have the student discuss questions or comments about the video. Part 2 25 min Radio Waves/Calculating Wavelength and Frequency 1. Have students work in their gr Sheet. 2. If time allows, complete the Extension activity found in the Teacher Sheet LPRadio Waves Tips and Hints Guide discussion towards student interest and curiosity. Follow the instructions in the LP Radio Waves- Teacher Sheet.

5 Teacher Sheet- Lesson Plan Radio Waves EMR: Investigation LESSON PLAN: Radio Waves and the Electromagnetic Spectrum Objective: Understand radio waves and how they relate to the electromagnetic spectrum. Determine wavelength and frequency of radio waves. Materials: 1. Reference materials (included) 2. Student Handout 3. Scientific Notation resource page (included) Procedure: 1. Engagement : Intro of the activity A. After the discussion from 2.1, ask the students to identify where on the Electromagnetic spectrum radio waves are located. B. Have a discussion of the use of scientific notation. 2. Exploration: Read and discuss reference material. Looking at the picture in the reference material and talk about things in their lives and how they relate to the picture. (i.e. Radio, Microwave, X- Ray machines) 3. Explanation: Introduce the formula and how it relates to Radio waves. Complete problems. 4. Extension: Students can research other machines and determine their position on the electromagnetic spectrum. 5. Evaluation: Show understanding of the concepts in the development of the response of the RFP

6 Teacher Sheet- Lesson Plan Radio Waves EMR: Investigation Educator Page 1. Engagement: A. Discussion/Warm up prompts to start discussions B. Using the Electromagnetic Spectrum chart, where are RADIO WAVES? Predict which waves are the longest AM or FM? If you had a box of 10 marbles, how many boxes would you have if you had 10!, 10!, 10!", 10!"? What makes 10! + 10! different than 10!? Notice in the first and last columns that the power of 10 is the same as the number of zeros in the number. So the speed of light 3 10! Meters per second is the same as 300,000,000

7 Teacher Sheet- Lesson Plan Radio Waves EMR: Investigation STUDENT RESOURCE Scientific Notation

8 Teacher Sheet- Lesson Plan Radio Waves EMR: Investigation STUDENT REFERENCE 2-3Exploration/Explanation Wavelength and Frequency of Radio Waves Radio waves are part of the complete electromagnetic spectrum. As you can see from the figure below, there are many different types of waves and these waves are different because they have different properties. One property to compare different kinds of waves is called the wavelength, or length of a wave. Wavelength is defined as the distance from one point on a wave to the corresponding point on the next wave. Since wavelength is a distance, the unit of wavelength is the meter (m). Radio waves have the longest wavelength compared to other types of waves in the figure. Another property used to compare waves is the frequency of a wave, which is defined as the number of waves created per second. As the waves propagate away from the source, the frequency also represents the number of waves that will pass a point per second. This unit of frequency is one divided by time (1/second) and scientists have given this frequency unit the name of hertz (HZ). The word "hertz" is named for Heinrich Rudolf Hertz, who was the first to conclusively prove the existence of electromagnetic waves. Radio waves have the lowest frequency compared to other types of waves. On your radio receivers, either in your car or at your home, the unit of measurement is also in Hz, but usually in one of two variations, khz and MHz (kilohertz, thousands of Hertz and megahertz, millions of

9 Teacher Sheet- Lesson Plan Radio Waves EMR: Investigation Hertz respectively). These variations are used to help identify the length of the wave, by using simple metric prefixes. The speed of a wave can be measured, and what scientists have discovered is that the speed of all types of electromagnetic waves is the same. Scientists call this speed the speed of light because visible light is the most familiar kind of wave to humans because we can see light! The speed of light is measured to be 300,000,000 m/s, which can also be written as, 3 10! meters per second (approximately 186,000 miles per second!) Frequency, wavelength and speed are related by the equation: c = fx where c is the speed of light x is the wavelength in meters f is the frequency in Hertz (Hz) Example problem : The network for the Georgia Bulldogs Football team is WSB AM 750kHZ. Find the wavelength of a radio wave with the frequency 750 khz. f = 750 khz = ! Hz = ! c =3 10! x=? (solve for the wavelength) Solve for x c = fx!! c =!! (fx)!! = x c = fx

10 Teacher Sheet- Lesson Plan Radio Waves EMR: Investigation 3 158!!"!!.!!"! =! x!"!!.!!"! x =.4 x 10! m when dividing two numbers in scientific notation divide the first numbers then divide the powers of ten!"!!"! re- write in scientific notation x = 4. x 10! m Locate the frequency on the radio dial above. Predict the wavelength for V103, Streetz 94.5, 99X and 1380 WAOK. Find the wavelengths for the following radio waves: MHz 94.5 MHz 99MHZ 1380 khz The longest frequency found on the FM dial

11 Teacher Sheet- Lesson Plan Radio Waves EMR: Investigation Educator Page 4. Extension: Have the students identify as many possible types of electromagnetic waves that they can (microwaves, heat lamps infrared, x- ray machines, the Hulk- gamma rays). Have students research them and determine their wavelength.

12 Student Sheet- Radio Waves EMR: Investigation Scientific Notation

13 Student Sheet- Radio Waves EMR: Investigation Wavelength and Frequency of Radio Waves Radio waves are part of the complete electromagnetic spectrum. As you can see from the figure below, there are many different types of waves and these waves are different because they have different properties. One property to compare different kinds of waves is called the wavelength, or length of a wave. Wavelength is defined as the distance from one point on a wave to the corresponding point on the next wave. Since wavelength is a distance, the unit of wavelength is the meter (m). Radio waves have the longest wavelength compared to other types of waves in the figure. Another property used to compare waves is the frequency of a wave, which is defined as the number of waves created per second. As the waves propagate away from the source, the frequency also represents the number of waves that will pass a point per second. This unit of frequency is one divided by time (1/second) and scientists have given this frequency unit the name of hertz (HZ). The word "hertz" is named for Heinrich Rudolf Hertz, who was the first to conclusively prove the existence of electromagnetic waves. Radio waves have the lowest frequency compared to other types of waves. On your radio receivers, either in your car or at your home, the unit of measurement is also in Hz, but usually in one of two variations, khz and MHz (kilohertz, thousands of Hertz and megahertz, millions of

14 Student Sheet- Radio Waves EMR: Investigation The speed of a wave can be measured, and what scientists have discovered is that the speed of all types of electromagnetic waves is the same. Scientists call this speed the speed of light because visible light is the most familiar kind of wave to humans because we can see light! The speed of light is measured to be 300,000,000 m/s, which can also be written as, 3 10! meters per second (approximately 186,000 miles per second!) Frequency, wavelength and speed are related by the equation: c = fx where c is the speed of light x is the wavelength in meters f is the frequency in Hertz (Hz) Example problem : The network for the Georgia Bulldogs Football team is WSB AM 750kHZ. Find the wavelength of a radio wave with the frequency 750 khz. f = 750 khz = ! Hz = ! c =3 10! x=? (solve for the wavelength) Solve for x c = fx!! c =!! (fx)!! = x c = fx

15 Student Sheet- Radio Waves EMR: Investigation 3 163!!"!!.!!"! =! x!"!!.!!"! x =.4 x 10! m when dividing two numbers in scientific notation divide the first numbers then divide the powers of ten!"!!"! re- write in scientific notation x = 4. x 10! m Locate the frequency on the radio dial above. Predict the wavelength for V103, Streetz 94.5, 99X and 1380 WAOK. Find the wavelengths for the following radio waves: MHz 94.5 MHz 99MHZ 1380 khz The longest frequency found on the FM dial The smallest frequency found on the AM dial.

16 Teacher Edition EMR: Investigation Investigation 3.2 Explain (~40 minutes) Preparation: Bookmark the site on each student computer. Install the Simulated Oscilloscope on a class set of I- pads, prepare I- 3.2 PPT. Group Work Part 1: 15 Min Oscilloscope Demonstration Part 2 20 min Calculate frequency and wavelength Overview: Engage Students visualizing and manipulating waves using an oscilloscope Students compute wavelength and frequency of electromagnetic waves. Students gain deeper understanding of electromagnetic waves Materials: I- Pads with the simulated oscilloscope, computers with associated bookmark, document camera, engineering notebook and calculators. Opening (5-7 min): In their engineering notebook, have students summarize the graphic on the I- 3.2 Opening Activity PPT. Student Actions Teacher Actions Level and Indicator of Understanding Students will manipulate a simulated oscilloscope to gain understanding of the properties of waves.. Students will practice calculating wavelength and frequency. Demonstrate the use of the simulated oscilloscope. Observe calculations and reinforce operations with exponents. Students should record their observations of the oscilloscope manipulation in their engineering notebook. Students will record the frequency and wavelength calculations of at least 3 waves on the electromagnetic spectrum in their engineering notebook.

17 Teacher Edition EMR: Investigation Daily Plan Investigation 3.2 Explain (~40 minutes)) Essential Questions: How can EMR be collected and measured? Suggested Activities Opening: 5-7 Min 1. In their engineering notebook, have students summarize the graphic on the I- 3.2 Opening Activity PPT. Part 1: 15 Min- Oscilloscope Demonstration 1. Demonstrate the use of the simulated oscilloscope on the I- Pad using a document camera. 2. Demonstrate the manipulation of amplitude and frequency on one wave. 3. Have students in their groups manipulate the amplitude and frequency on several waves. 4. Have the students write descriptions of their observations in their engineering notebook. Part 2 20 min Calculate frequency and wavelength 1. Have students visit the following website bookmarked on their computer: hange/p_emspectrum_interactive.htm 2. Instruct the students to place the point on the green triangle located under the chart of the EM Spectrum. 3. Have the students slide the green arrow to the right and back to the left. Student should observe the two bottom boxes, Wavelength and Frequency and Energy, and write their observations in their engineering notebook. 3. Demonstrate how to verify the wavelength of a chosen wave: For example- slide the green triangle so that the green line is at 10! on the Frequency line. Model for the student how to verify the wavelength by using the appropriate equation below to solve for wavelength. Tips and Hints Use Teacher Sheet Simulated Scope for instructions on how to use the Agilent Simulated Scope for I- pad. Display the equations. Review operations using scientific notation using a calculator.

18 Teacher Edition EMR: Investigation Daily Plan Investigation 3.2 Explain (~40 minutes)) Essential Questions: How can EMR be collected and measured? Suggested Activities Part 2 20 min Calculate frequency and wavelength 4. Have student to observe the two boxes below the EMR spectrum graph labeled Wavelength and Frequency and Energy. 5. Discuss what is happening in both pictures. 6. Demonstrate how to verify the frequency of a chosen wave. For example- slide the green triangle so that the green line is at 10! on the wavelength line. Model for the students how to verify the frequency by using the appropriate equation below to solve for frequency. 7. Have student to observe the two boxes below the EMR spectrum graph labeled Wavelength and Frequency and Energy. 8. Discuss what is happening in both pictures. 9. Have students choose 3 wavelengths along the spectrum to verify and solve for the frequency. Write their solutions in their engineering notebook along with the observations made from the Wavelength and Frequency and Energy Boxes. 10. Have students choose 3 frequencies along the spectrum to verify and solve for the wavelength. Write their solutions in their engineering notebook along with the observations made from the Wavelength and Frequency and Energy Boxes. Tips and Hints Display the equations. Review operations using scientific notation using a calculator.

19 Teacher Edition EMR: Investigation Daily Plan Investigation 3.2 Explain (~40 minutes)) Essential Questions: How can EMR be collected and measured? Key Equations: 1. c = wavelength frequency 2. 3.!!"#$%#&'( = wavelength!!"#$%$&'(! = frequency c = 3.0 x 10!

20 Teacher Sheet- Simulated Scope EMRs: Investigation Agilent Oscilloscope Mobile Guide Download the I- Pad App Agilent Oscilloscope (free) After it has been downloaded, Tap once on the Oscilloscope icon. Select Simulate Scope

21 Teacher Sheet- Simulated Scope EMRs: Investigation 3 169

22 Teacher Sheet- Simulated Scope EMRs: Investigation To adjust the amplitude of a wave 1. Choose one of the channels (1,2,3, or 4) 2. Turn off the other channels by pushing the number button. For Example: To turn off channel 1, hit the button labeled 1 (yellow). 3. To modify the amplitude, change the voltage by pressing the voltage button next to the channel number button. Choose any of the voltages that appear in the pop up box.

23 Teacher Sheet- Simulated Scope EMRs: Investigation To modify the frequency press the main timebase button and choose another setting: 5. Allow your students to explore after you have demonstrated these two features. 6. Use the Help button for the explanation of features shown in the figure found below the start screen.

24 ELECTROMAGNETIC RADIATION I- 3.2 OPENING ACTIVITY Summarize the picture in your Engineering notebook. Funded by the Georgia Dept. of Ed. through the U.S. Dept. of Ed. Race to the Top grant 172